Titanium base alloy



Patented May 13, 1952 TITANIUM BASE ALLOY Robert I. Jaffee and Horace It. Ogden, Columbus,

1 Ohio, assignors, by mesne assignments, to Remington Arms Company, Inc., Bridgeport, Conn, a corporation of Delaware No Drawing. Application December 2, 1950, Serial No. 198,917

4 Claims.

1 This invention relates to titanium base alloys, and contemplates certain structurally useful quaternary alloys of titanium with aluminum, chromium and molybdenum, as well as a pro- 2 0.5%, if the alloys are to possess good ductility as cast or as Worked and annealed.

It has been 'found, however, that the presence of a small amount of carbon, say 0.05% to 0.3%,

cess for the preparation of such alloys in a ductile 5 with or without 0.01% to 0.15% nitrogen or 0.01% condition. to 0.25% oxygen, or both oxygen and nitrogen, In application of Jafiee and Ogden, Serial No. may be beneficial. Among the alloys of this in- 122,5'77, filed October 20, 1949, now Patent No. vention are those made either with a commer- 2,554,031, issued May 22, 1951, there are disclosed cial titanium base meeting such specifications, or certain structural alloys containin aluminum with a high purity titanium base containing simiand molybdenum. In the application of Jaiiee lar amounts of added carbon, oxygen and/or and Ogden, Serial No. 122,576, filed October 20, nitrogen. Thus, within the purview of the in- 1949, there are disclosed certain ductile alloys of vention are quaternary alloys containing from titanium with aluminum and chromium; also about 2% to about 5% aluminum, 1% to 6% chroseveral alloys of titanium and aluminum with mium and 1% to 6% molybdenum, as additions relatively small amounts of chromium and to a titanium base which may be of high purity or molybdenum. The present application is a conmay contain up to 0.15% nitrogen, 0.25% oxygen tinuation-in-part of Application Serial No. /or car n; he t l itro y 122,576. and carbon content preferably not exceeding The titanium base metal used in the present 29 0.5% These ll ys are of hi h t il str h. alloys may contain substances or impurities beand of such ductility as to permit their forming sides titanium, as normally found in either high and fabrication by the usual metallurgical procpurity titanium or commercially pure titanium. esses, such as rolling, drawing and forging. If It may be, for example, a high purity or iodide y the combined content of chromium and molybprocess titanium, as produced according to the denum is relatively low, say about 2.5%, the alloy Van Arkel U. S. Patent No. 1,671,213. Altermay b prepared for use by quenching from a natively, it may be a commercial titanium, as temperatureof 850 C. to 950 C., and thereafter produced, for example, by magnesium-reduction annealing. Typical alloys of this group, and processes, such as the process of U. S. Patent No. their properties, are as follows:

Tensile properties Compo ition wi l: Propor 01? 027 C13}; 513;; (BalanceTi) Hard- Limit OiIS t Oiis t ig gm QEZ 11035 in ti 2,205,854, to Kroll, or modifications thereof; provided that the carbon, oxygen and nitrogen contents of these alloys, hence of the base metal, should not exceed 0.5%, 0.25% and 0.15% respectively, nor should they total more than about Quaternary alloys having a, higher content of molybdenum and/or chromium, as quenched from the all-beta field, possess acceptable ductility, but are severely embrittled by subsequent :55 exposure to moderately elevated temperatures.

Hitherto it has been believed that alloys containing for example aluminum and 4% each of chromium and molybdenum were inherently too b-rittle for structural use. It has been found, however, that if such alloys are slowly cooled from a temperature. high in the two-phase field or within" the all-beta field, say 850 C. t0 950 0., they are not only ductile as cooled but substantially retain their ductility after prolonged eX- posure to temperatures as high as 400 C. In. a typical processing, the alloy is heated to9'00 C., and retained at this temperature for about threequarters of an hour. Thereafter; it isccol'ed at a rate of about 1 per minute to a temperature oi about 500 C., after which cooling may be more rapid. The soaking may be; performed.- in an electric furnace and, after soaking, the furnace control set back 60 every hour until the tempera= ture is below about 500 C., after which the heat is turned completely off, the workremaining in the furnace until both are reduced substantially to room temperature. The resulting alloys are not only ductile but remain ductile" upon subse quent' exposure to elevated temperatures such as 300 or 400C. The slowcooling has the effect of transforming a maximum amount of the metal from the high temperature beta phase to the lowtemperature alpha phase, thus avoiding the embrittling coherency hardening brought about by the aging transformation of the-unstable beta of quenched alloys;

Bend ductility is a more severe and practical test of utility than is tensile elongation. Bend ductility is measured as the radius, expressed as a multiple of specimen thickness, at which the specimen can be bent" to an angle of without fracture Typical alloys" withinthe present invention, their hardness and bend ductility; as cooled in themanner above described and afterelevated l temperature exposure, areas follows:

Delayedcooling from 9001 0.

4 It will be seen that not only are these alloys ductile in the slow cooled condition, but that they largely retain their ductility after as much as 200 hours storage at 400 C. The same alloys in as quenched condition show hardness and ductility comparablewith' the slow cooled'icondition. but storage for 64 hours at 300 C.', raises average Vickers hardness well over points and virtually destroys all bend ductility. It is' thus in slow-cooled, or slow-cooled and aged condition,

to 5% aluminum/1% chromium, 4% molybdenum, balance titanium.

ROBERT L JAFFEE. HORACE a. OGDEN.

REFERENCES CITE-D The following references are of reoordi in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,188,765 Young; Jam 30.19% 2,467,367 Austin Apr. 1 95.19.49 2,490,571 Anicetti -a. ....,Dec"-. 6-,,1949 2,554,031! Jaffee etal. an.-- May 22;. i

V Befbr-fistbraga l Storegfiggmat storciugllldiirsrat CotmiosltiorMBal emcee-Ti): I

Vlckers Bend Vickers Bend Vickers Bend- Hardness Radius: Hardness Radius: Hardness Radius" T v T T s55 2.0 362 j 2.2 V 382 6.7

347 as 390 2. (i 385 1 8:1 

1. A DUCTILE ALLOY CONSISTING ESSENTIALLY OF 2% TO 5% ALUMINUM, 1% TO 6% CHROMIUM, 1% TO 6% MOLYBDENUM, BALANCE TITANIUM. 